The present invention relates to a method for automatically bending the ends of profiled elements and the like, particularly rods for reinforced concrete, and to a machine for performing the method.
It is known that shaped rods, used for example to produce reinforced-concrete frames, are generally produced by means of devices which subject the rod, in coils or cut into bars, to an adapted plurality of bendings. These forming machines usually have at least one bending unit provided with a bending head which has a central pivot, an abutment and an eccentric bending pivot.
More particularly, bending machines are currently known which allow to produce, directly from coils of rod, a large number of different products, such as open or closed stirrups, circular or polygonal spirals, straight bars and the like. These machines conveniently have a plurality of elements for straightening and feeding the rod, a unit for cutting the rods to be bent and one or more bending units of the above-mentioned type arranged in series.
A specific problem that occurs in the field being considered is the need to provide rods which are bent at their opposite ends according to preset profiles. Bending both ends of the rods is in fact generally complicated and requires a relatively long time which causes limited productivity.
For this purpose, forming machines are known which have two bending heads that allow to separately bend the opposite ends of the rods. Said forming machines have a complicated structure and do not allow to form stirrups except with severe limitations.
It is also known to use machines meant to form stirrups, commonly known as stirrup benders, provided with auxiliary units which allow them to act as forming machines. These machines, however, have a very long operating time for producing rods bent at their ends and therefore cannot achieve high productivity.